For decades Marthe Cohn never spoke about the role she played during the Second World War. It was assumed, like so many, she kept her head down and waited for it to be over. It was only in 2002 when her autobiography Behind Enemy Lines: The True Story of a French Jewish Spy in Nazi Germany came out that friends and family realized that the kindly old woman, who lived with her husband in a quiet California town, had played a crucial role during the war.

Cohn, who celebrated her 100th birthday with a "drive-by" celebration due to social distancing required by the COVID-19 pandemic, had hoped to attend the Los Angeles premiere of a newly made documentary chronicling her life, Chichinette: How I Accidentally Became a Spy. The film had previously premiered at the Haifa International Film Festival, where it won the audience award.

It details her life growing up in France near the German border, and how in 1944 she joined the Intelligence Service of the French Army.

"The crazy part of the story was that nobody knew she was a spy," filmmaker Michael Potter, who grew up across the street from Cohn, told The San Jose Mercury News.

She had been happy to take the secret to the grave, but when her brother contracted Parkinson's disease in 1996, she said she felt it was time to share the story, and in 1998 began to write the book. Since her autobiography was published she's given thousands of public talks, and along the way shared details few knew. That included the awards for bravery including the Cross of the Order of Merit, Germany's highest honor; multiple French awards including the Croix de Guerra and Chevalier de la Légion d'honneu, the highest order for military and civil merits; and most notably the Woman of Valor award from the Simon Wiesenthal Center.

Unlike movie spies who are crack shots, skilled in unarmed combat, and provided with high-tech gadgets, Cohn was recruited for her language skills, while her memory proved to be her most important tool.

Born Maria Hoffnug and a nurse by trade, Cohn was one of seven children who grew up in an Orthodox Jewish family. Along with her sister Stephanie, she helped people escape to unoccupied France – but in June 1942, Stephanie was arrested and sent to the Route de Limoges, a camp for foreign Jews in German-occupied France.

While an effort to organize Stephanie's escape was planned, in the end Stephanie opted not to put the rest of the family at risk. She was transferred on Yom Kippur 1942 to an unknown destination. Only after the war did the family find out it had been to Auschwitz, where Stephanie was murdered by the Nazis.

If that was all to the story, Marthe Cohn would have already done more than her part during the war. But even as the tide turned and victory in sight, she felt she could do more. When Paris was liberated in August 1944, Cohn enlisted in the French military, where she met a colonel who learned she read and spoke German.

With practically every German man in uniform, it would be impossible for a French agent who was male to be unnoticed. A woman, on the other hand, could blend in and hide in plain sight.

She accepted a transfer to the Intelligence Service, and crossed the border to Germany undetected through Switzerland. Cohn's story was that she was trying to find her missing fiancée, and soon she returned to nursing but this time for the Germans, and more importantly she was a spy for France. While it was a brief time, it was still quite dangerous.

It was impossible to relay the messages back, so everything had to be memorized.

After three weeks she returned to France with important information for the Intelligence Service. She confirmed that the seemingly impregnable Siegfried Line northwest of Freiburg had been evacuated, and relayed the location of the German Army in the Black Forest. Cohn continued to work as a spy from December 1944 through January 1947, monitoring the post-war situation in Germany.

After the war, she met her future husband, American Major Cohn, and to the two married and moved to the United States. For her 100th birthday, she received hundreds of emails and phone calls, including from the presidents of Germany and Israel.

"It was amazing to me so many people made such an enormous effort," she told The Mercury News.

We should all remember the enormous effort she made during the war.

Peter Suciu is a Michigan-based writer who has contributed to more than four dozen magazines, newspapers and websites. He is the author of several books on military headgear including A Gallery of Military Headdress, which is available on Amazon.com.